A style of Jamaican Reggae. First there was Ska, which evolved into Reggae which has several styles: Rock Steady, Rub-A-Dub, Dancehall etc.
The term "Rub-a-Dub" comes from a dance style where the man and woman rub up very close together and grind their hips to the beat.

Most of the music of Bob Marley and the Wailers is in a Rub-A-Dub style.

A bum, homeless person, or undesirable of either sex. The term does apply to street musicians, the working poor, or temporarily homeless people who keep themselves tidy. It also does not have racial connotations. Rather, it refers to people who are poor, filthy and homeless as a result of their own character flaws, such as laziness, surliness, alcoholism, drug addiction, etc.

"Boy, there are a lot of rub a dubs downtown today. Is somebody giving away hot dogs?"

Originally begun in the deep Bronx, New York. Not just a statement, but a way of life. A singular statement which relies on multiple synonmys in order to create a message of thug nature and a gangbanging mentality. Created by the notorious gangster Big Tony a.k.a. Big Dub Tony Maroni.

Synonyms:Rub/snub/tub/grub/shrub/dub/bub/knub/club/sub/flub/pub/stub/cub
Chilin in the club, rockin that all black snub, girl trippin cause i just smoked a dub of that indo grub, she hollas don p i yell rub a dub dub. This bub walks up with a wack ass elbow knub, he aks to smoke a shurb. I go listen bub, you wanna take this to the pub, what, you wanna go down periscope to the sub. Youz looks like a baby cub, while I got mad stub on face grub, peace bub.